These are apps executed in blockchain. Bitcoin, being a transaction-focused peer-to-peer network, happened to be the first ever decentralized application. The opportunity to make smart contracts and write executable code within blockchain has given birth to all sorts of decentralized applications. Besides, DAps can be quite independent from any particular blockchain, operating as entirely stand-alone applications. Example: MadeSafe, a distributed data storage application. In short, it operates like this: you make your disk space and up-time available to the network users and collect your premium for that; alternately, you can upload your data to the network in exchange for your service. There had been similar projects in the past (for example, Wuala), but now, for the first time ever, they are founded on economic principles: you simply offer your space and get paid. So far there is no certainty whether the project will survive.
Internet sources give a list of criteria an application must satisfy to be called a DApp:
- A Dapp must be fully open-code, it must operate as a stand-alone application and no organization may be able to claim possession of the greater part of its tokens. A Dapp may adapt its protocol in response to suggested improvements and market feedback, but all changes must be adopted by consensus of all its users.
- A DApp’s data and operating reports must be encrypted and stored in a public domain, the so called decentralized blockchain, to avoid any potential network outage.
- A DApp must require a cryptographic token (bitcoin or original app token) for access to it. Every bit of input contributed by miners must be rewarded in DApp’s tokens.